Vehicles that use motors as a power source such as hybrid cars and electric cars have increased in recent years. In a motor used as a power source, a resolver is often used as a rotation sensor for detecting rotation position of a rotary shaft of the motor for accurate position control. This resolver includes a resolver rotor fixed to the shaft of the rotor of the motor, and a resolver stator mounted in a case supporting the rotary shaft.
Mounting accuracy, etc. of these parts are essential requirements for ensuring detection accuracy of the resolver, and various approaches are under consideration.
Patent Document 1 discloses a technique relating to a resolver rotor.
Disclosed is a structure in which a shaft is provided with a stepped portion, and a rotor, a bush, and a rotary transformer are mounted in a stacking manner on the shaft. An end portion of the shaft is deformed by crimping or clinching such as to cover one end of the rotary transformer, whereby the rotor, bush, and rotary transformer are held on the shaft.
The structure for the shaft, rotor, bush, and rotary transformer is thus simplified to improve ease of assembly and to enable cost reduction.
Patent Document 2 discloses a technique relating to a rotor of a magnet generator.
In a joint between a boss and an iron cup of the rotor of the magnet generator, when the boss, which is fixed to a rotary drive shaft, is fixed to the iron cup that is arranged concentrically on the outer periphery of the boss and having permanent magnets on its inner circumferential surface, an outer peripheral portion of the boss and an inner peripheral portion of the iron cup make contact with each other, and the iron cup also abuts on an iron cup receiving portion provided on one side of the outer peripheral portion of the boss. Further, a crimped portion provided on the other side of the outer peripheral portion is deformed so that the boss is axially fixed to the iron cup. This joint between the outer peripheral portion and the inner peripheral portion is located in a position where the radial tensile stress caused by an axial load will be minimum.
Patent Document 3 discloses a technique relating to a fixture structure of a resolver rotor.
The resolver rotor is provided with a plurality of cut-outs in an inner peripheral hole section and is disposed at a predetermined position relative to a shaft. Resin parts are then formed by injection molding for the purpose of retaining the rotor core to the shaft, so that the cut-outs formed in the hole of the resolver rotor are also filled with resin flowing therein. As a result, resin layers are formed on both sides in the direction of rotation axis of the resolver rotor, so that the resolver rotor is integrally held on the shaft. A key formed in the hole of the resolver rotor is fitted in a key groove formed in the shaft to prevent displacement of the resolver rotor relative to the shaft in the rotating direction.
Patent Document 4 discloses a technique relating to a fixture structure of a rotation angle sensor.
Disclosed is a structure in which a resolver rotor is lightly press-fitted onto a stepped portion provided in a motor rotor, and a resilient ring and a pressing ring are mounted thereon and pressure is applied, so that the resolver rotor is fixed to the motor rotor. The friction between the resilient ring and the pressure ring holds the resolver rotor on the motor rotor.